Influence of Danazol on gonadotropin secretion and synthesis by rat pituitary cells in cultures. Comparison with gonadal steroids.

Increasing concentrations of estradiol, testosterone, progesterone (1.10(-10) to 1.10(-7] and Danazol (1.10(-9) to 1.10(-6) M) have been added to male rat pituitary cells maintained in monolayer cultures for a preincubation period of three days followed by a six hour incubation with or without GnRH (1.10(-8) M). Concentrations of LH and FSH have been assessed in the culture media and in the cells at the end of the experiments allowing an estimation of the influence of these steroids on gonadotropin release and synthesis. In these experimental conditions, estradiol does not modify basal and GnRH induced FSH release and synthesis but reduces the GnRH-induced response of LH. Testosterone and progesterone stimulate synthesis of FSH but inhibit synthesis and secretion of LH in the presence of GnRH. These results have been compared with those of literature. Danazol, in the same experimental conditions, stimulates synthesis of gonadotropins and simultaneously inhibits their release induced by the presence of GnRH. We conclude that Danazol is able to act at the pituitary level as testosterone which is in good agreement with its androgenic properties.